Many people desire to keep skin color white. On the other hand, there are also people who have a resistance to strange whiteness of skin or uncomfortable whiteness of skin that has appeared owing to the recently developed various kinds of whitening cosmetics. Accordingly, whitening to become a fair-complexioned and natural-looking white skin has been desired. As for external preparations for skin for this purpose, the field of cosmetics called “lightening cosmetics” has recently become common (see, for example, Patent documents 1, 2, and 3). However, although the concept of lightning cosmetics has been built, because there was no active ingredient responsible for the substance, the situation has been where it must be said that there is no effective lightening cosmetic. In order to obtain such an effect, it is said that a lightening cosmetic needs to have a not excessive but appropriate inhibitory effect on melanin production, an excellent skin conditioning effect, and an excellent moisturizing effect in combination. However, such a material and a combination of components providing such effects have not been known yet.
Examples of a “whitening agent” that is a component inhibiting melanin production and has already been developed include: placenta extract; ellagic acid and salts thereof; ascorbic acid and derivatives thereof; tranexamic acid and salts thereof; kojic acid and salts thereof; arbutin and salts thereof; and 4-n-butyl resorcinol and salts thereof (see, for example, Non-patent document 1).
An extremely small amount of centaureidin, which is one of the compounds represented by the following general formula (1), is known to be present in a plant of the genus Achillea sp. of the family Compositae, such as Achillea millefolium (see, for example, Non-patent document 2). Moreover, it has already been known that a component of a plant of the genus Achillea sp. of the family Compositae, such as Achillea millefolium, has whitening action (see, for example, Patent documents 4, 5, and 6). It has also already been known that whitening is achieved by inhibiting elongation of dendrites of melanocytes (see, for example, Patent documents 7 and 8).
[Non-patent document 1] Takeda et al. ed., “Usefulness of Cosmetics. Advances and Future Perspective in Evaluation Technology. (Keshohin no Yuyosei. Hyokagijyutsu no Shimpo to Shoraitembo.)”, The Yakuji Nippo Limited, Mar. 31, 2001.
[Non-patent document 2] Glasl S., et al., Z. Naturforsch., 2002(11-12), 976-982
[Patent document 1] JP 2003-212714 A
[Patent document 2] JP 2000-502359 A
[Patent document 3] JP 08-48620 A
[Patent document 4] JP 08-104646 A
[Patent document 5] JP 11-349435 A
[Patent document 6] JP 2001-316214 A
[Patent document 7] JP 2003-113027 A
[Patent document 8] JP 2003-81807 A